Abstract
The article presents the results of a study of the composition of petroleum bituminous rocks of the Alimbai field located in the Zhylyoi district of the Atyrau oblast to the north-east of the city of Kulsary (Western Kazakhstan). On the territory of the Republic of Kazakhstan, according to experts, reserves of natural bitumen are 1 billion tons, and petroleum bituminous rocks - over 15-20 billion tons. The purpose of this work was to study the organic components of petroleum bituminous rocks of this field as an additional source of fuel, energy and chemical resources. Samples of oil bituminous rocks of different depths were taken for the study. As the results of the analysis showed, the yield of the organic part of the investigated deposit ranges from 3.4 to 13.7% by weight. Natural bitumens of the Alimbai deposit are characterized by a content of oils from 57.8% to 71.3% by weight. In connection with the increase in the depth of occurrence of oil bituminous rocks, a decrease in molecular weight from 587 to 476 amu is observed. It is shown that the content of paraffin-naphthenic and monocycloaromatic hydrocarbons is much higher than that of bi- and polycycloaromatic hydrocarbons. The distribution of hydrocarbons by fractions shows the predominant content of paraffin-naphthenic hydrocarbons and alcohol-benzene resins with a low content of asphaltenes and benzene resins. The obtained results show that even within a small thickness of the rock there are processes of migration of organic matter by analogy with secondary oil migration processes.